This is a note to let you know that I've just added the patch titled
MIPS: pci: lantiq: restore reset gpio polarity
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mips-pci-lantiq-restore-reset-gpio-polarity.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit cf5ece923e1d804b10de1bd03d3383336e456370
Author: Martin Schiller <ms@xxxxxxxxxx>
Date: Fri Jun 7 11:04:00 2024 +0200
MIPS: pci: lantiq: restore reset gpio polarity
[ Upstream commit 277a0363120276645ae598d8d5fea7265e076ae9 ]
Commit 90c2d2eb7ab5 ("MIPS: pci: lantiq: switch to using gpiod API") not
only switched to the gpiod API, but also inverted / changed the polarity
of the GPIO.
According to the PCI specification, the RST# pin is an active-low
signal. However, most of the device trees that have been widely used for
a long time (mainly in the openWrt project) define this GPIO as
active-high and the old driver code inverted the signal internally.
Apparently there are actually boards where the reset gpio must be
operated inverted. For this reason, we cannot use the GPIOD_OUT_LOW/HIGH
flag for initialization. Instead, we must explicitly set the gpio to
value 1 in order to take into account any "GPIO_ACTIVE_LOW" flag that
may have been set.
In order to remain compatible with all these existing device trees, we
should therefore keep the logic as it was before the commit.
Fixes: 90c2d2eb7ab5 ("MIPS: pci: lantiq: switch to using gpiod API")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Martin Schiller <ms@xxxxxxxxxx>
Signed-off-by: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/mips/pci/pci-lantiq.c b/arch/mips/pci/pci-lantiq.c
index 80f7293166bb7..0dabee7a1c511 100644
--- a/arch/mips/pci/pci-lantiq.c
+++ b/arch/mips/pci/pci-lantiq.c
@@ -124,14 +124,14 @@ static int ltq_pci_startup(struct platform_device *pdev)
clk_disable(clk_external);
/* setup reset gpio used by pci */
- reset_gpio = devm_gpiod_get_optional(&pdev->dev, "reset",
- GPIOD_OUT_LOW);
+ reset_gpio = devm_gpiod_get_optional(&pdev->dev, "reset", GPIOD_ASIS);
error = PTR_ERR_OR_ZERO(reset_gpio);
if (error) {
dev_err(&pdev->dev, "failed to request gpio: %d\n", error);
return error;
}
gpiod_set_consumer_name(reset_gpio, "pci_reset");
+ gpiod_direction_output(reset_gpio, 1);
/* enable auto-switching between PCI and EBU */
ltq_pci_w32(0xa, PCI_CR_CLK_CTRL);
@@ -194,10 +194,10 @@ static int ltq_pci_startup(struct platform_device *pdev)
/* toggle reset pin */
if (reset_gpio) {
- gpiod_set_value_cansleep(reset_gpio, 1);
+ gpiod_set_value_cansleep(reset_gpio, 0);
wmb();
mdelay(1);
- gpiod_set_value_cansleep(reset_gpio, 0);
+ gpiod_set_value_cansleep(reset_gpio, 1);
}
return 0;
}
